Higher-seeded teams went 5-3 last year and 6-2 the year before that in the round of 16. That two-year total of 11-5 SU contrasts starkly with the 12-4 ATS streak enjoyed by underdogs in those same 16 games.

Include the 2011 tournament and underdogs are on a 17-7 ATS spree at the betting window.

Only one of the top seeds is gone as Florida, Arizona and Virginia remain. Not that bettors should be flocking to bet on the No. 1 seeds based on recent history. After their 0-3 ATS record in 2013, top seeds are mired in a 2-8 ATS funk over the past three Sweet 16 rounds.

Virginia is a rare underdog against No. 4 Michigan State. Since 1996, a top seed was a dog to a fourth seed just once. In that case, No. 4 Louisville prevailed against Washington back in 2005.

And top seeds should be very careful with No. 4 seeds, after losing two of three games to them in 2013 at this stage.

In the Midwest, state rivals Louisville (seeded fourth) face dangerous 8-seed Kentucky. There have been just three games involving 8 seeds vs 4 seeds and the lower seeds won all three.

Also in the Midwest, No. 2 Michigan faces No. 11 Tennessee. This matchup has occurred five times since 2002 and the No. 2 seeds are 5-0 SU, 4-1 ATS in those games.

In the West, an intriguing matchup of No. 6 Baylor and No. 2 Wisconsin is made more interesting by these trends: No. 2 seeds are 8-1 SU since 2002 vs 6 seeds, but the lower seeds have been money in the bank for bettors at 7-2 ATS.

The biggest favorite this week is Arizona at -7.5 against San Diego State, according to the March Madness odds menu.